Effects of Reducing Sedentary Time on Glucose Metabolism in Pakistani Immigrant Men

Purpose: To examine the association between changes in objectively measured overall physical activity (PA), with changes in fasting and postprandial plasma insulin, C-peptide and glucose concentrations, in type 2 diabetes prone Pakistani immigrant men living in Norway and to examine whether this association is explained by changes in moderate-and-vigorous PA (MVPA) or changes in sedentary time.

Methods: The current study is a secondary cohort analysis on data collected from the Physical activity and minority health study, a randomised controlled trial aimed to increase the PA level, and not sedentary time per se, in a group of sedentary Pakistani immigrant men (n=150). For the present analyses the two groups were merged and a cohort analysis performed. Overall PA (counts per min) and its sub-components, sedentary time and MVPA were measured with accelerometry. Outcome variables were measured after a 2-hour standardised glucose tolerance test.

Results: Change in overall PA was significantly associated with postprandial log transformed plasma insulin ([beta]=-0.002, 95% CI -0.003 to 0.000, P=0.008), C-peptide ([beta]=-2.7, 95% CI -4.9 to -0.5, P=0.01) and glucose concentration ([beta]=-0.006, 95% CI -0.01 to -0.002, P=0.002). Change in sedentary time was significantly and beneficially associated with changes in postprandial log transformed plasma insulin ([beta]=0.002, 95% CI 0.001 to 0.003, P=0.001), C-peptide ([beta]=3.7, 95% CI 1.5 to 6.0, P=0.001) and glucose concentration ([beta]=0.006, 95% CI 0.002 to 0.1, P=0.002) independent of changes in MVPA, waist circumference and other confounders.

Conclusion: Increasing overall PA by reducing sedentary time appears as important as increasing time spent at MVPA in relation to postprandial plasma insulin and glucose levels in diabetes prone immigrant men.